Recently, a color liquid crystal display is used in various fields such as a laptop computer, a desktop computer, a cell phone, a PDA, a car navigation device, a PND, a game machine, and a portable music player. The color liquid crystal display is provided with a liquid crystal cell and a backlight. As the structure of the backlight, a direct type structure in which a light source is provided directly below the liquid crystal cell through a diffusion plate, an edge light type structure in which a light source is provided on the side of a light guide plate, or the like is known.
For such backlights, optical members such as a light diffusing sheet for uniformly emitting light from the light source and a prism sheet for increasing front luminance are laminated on a light exit surface of a light guide plate or diffusing plate (Patent Document 1).